No abstract

Optical amplification of 11 orders of magnitude in a microlens-collimated, diode-laser-pumped regenerative amplifier has been demonstrated. The amplifier was seeded with 20-ps pulses from an FM mode-locked oscillator and with 0.9-ns pulses from a modulated diode laser. Seed pulses from both sources were amplified to energies exceeding 2.5 mJ. With the thermoelectric coolers and the Pockels cell electronics neglected, the diode-seeded system exhibited an electrical-to-optical efficiency of 2.2%.

We have demonstrated and characterized a Q-switched Nd:YAG laser under continuous operation for over 7 billion shots. Through periodic monitoring of the laser's vital signs, the system dynamics were decoupled to identify the sources of degradation. The initial and the final pump-laser diode wavelengths and powers were measured and compared. No evidence of an accumulative effect leading to optical damage at a fluence lower than the single-shot threshold was observed.

We have developed a unique numerical laser model by use of a commercial physical optics software package. The experimentally measured lasing threshold, slope efficiency, power output distribution, and phase front have been derived. This model is particularly powerful for monitoring the effects caused by thermal distortions encountered in power scaling lasers. Extrapolations have been made through parametric studies to predict changes required in the laser design that would optimize the performance of the laser.